The present invention pertains generally to implantable medical devices and, more particularly, to implantable medical devices which are capable of being implanted utilizing minimally-invasive delivery techniques. More particularly, the present invention relates to covered stents, stent-grafts and stent-graft-type devices that are implanted into anatomical passageways using minimally invasive delivery techniques. More specifically, the present invention comprises covered stents, stent-grafts and stent-graft-type devices that are fabricated entirely of biocompatible metals or of biocompatible materials which exhibit biological response and material characteristics substantially the same as biocompatible metals, such as for example composite materials (hereinafter referred to as “pseudometals” or by the property of being “pseudometallic”). Most specifically, the present invention relates to metal stents and metal stent covers wherein the metal stent cover is attached by at least one juncture between the metal stent at each of proximal and distal ends thereof.
Stents are typically lattice structures capable of adopting both a diametrically compressed configuration, for delivery to the site of deployment, and a diametrically expanded configuration, in which the stent presses outward and against the inner wall of the anatomical passageway to provide structural support to the vessel, restore and maintain vascular patency. Endoluminal stents, for example, are frequently used post-angioplasty to provide a structural support for a blood vessel and reduce the incidence of restenosis following percutaneous balloon angioplasty. For example, endovascular stents may be introduced to a site of disease or trauma within the body's vasculature from an introductory location remote from the disease or trauma site using an introductory catheter, passed through the vasculature communicating between the remote introductory location and the disease or trauma site, and released from the introductory catheter at the disease or trauma site to maintain patency of the blood vessel at the site of disease or trauma.
In many applications, it is desirable to provide a stent with a covering capable of conferring particularly desirable properties that the stent alone does not possess. For example, bare stents have been associated with significant restenosis rates and, due to the typically large fenestrations in the walls of the stent required to accommodate stent expansion from the compressed to the expanded diametric stage, permit particulate material, such as fragmented plaque, to pass from the vessel wall into the bloodstream. The relatively large fenestrations permit particulate material resident on the vascular walls, such as friable plaque or embolic material, to pass through the fenestrations and into the general circulation. Such undesirable effects may be reduced, however, by providing the stent with a covering over either the lumenal or ablumenal surfaces, or both surfaces, thereby forming a covered-stent or for purposes of this application, synonymously, a stent-graft.